Femtocell devices are small base stations designed for home or small business use. Femtocell devices operate in a small (<200 m) range and are designed to provide cellular coverage in the home or office. The typical femtocell device connects to a Security Gateway or Softswitch over an Interent Protocol (IP) connection, such as a DSL or broadband cable connection. The Security Gateway or Softswitch are intended to plug into the DSL or cable modem using a standard Ethernet cable.
Connecting a Femto Access Point (FAP) to an operator's network is the subject of standardization in various standards bodies. One solution is to connect the FAP through a Femto Gateway, or (FGTW) to an IP Multimedia Subsystem (IMS) network. This solution requires that the FAP or the FGTW contains a Session Initation Protocol (SIP) client, and that SIP (defined under RFC3261) is used to establish a session between the FAP and other entities in the network with which the FAP must communicate. Since the FAP is required to support legacy mobiles (e.g., subscriber stations) in any deployment, the FAP must support signaling associated with existing air interface specifications—such as, for example, cdma2000. The signaling messages sent to and from the Subscriber Station (SS) is defined by TIA-2000. The signalling messages are communicated to the core network entities that understand this signaling (e.g. a Mobile Switching Center (MSC)). Since the existing network standards for forwarding signaling information to the MSC (i.e., TIA-2001) do not support SIP, an interworking entity is utilized. The interworking entity allows the signaling information sent from the FAP to be forwarded to an MSC. Futher, the interworking entitiy allows return signaling from the MSC destined for the SS to be forwarded to the FAP using SIP. One such interworking entity is a MSC Femto Interworking Function (MFIF).
Current Femtocell networks do not allow for the transport of all information that the MSC needs to process important messages received at a SIP-based FAP from a legacy (e.g., cdma2000) SS. For example, when the SS sends a Registration message to the FAP, the FAP must include information about the SS's identity and other authentication data in order for the MSC to process the registration. The current definition of Presence Information Data Format (PDIF) does not allow for this information to be transported. Therefore, the MFIF is not be able to form the message properly to send to the MSC.
Therefore, there is a need in the art for an improved method of obtaining device information in a Femtocell. In particular, there is a need for a device that is capable of communicating location information via a Femto gateway using a session initiation protocol.